with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to ring carbon atoms

Full Title

Heterocyclic compounds containing 1,2-diazine or hydrogenated 1,2-diazine rings > not condensed with other rings > having three double bonds between ring members or between ring members and non-ring members > with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to ring carbon atoms